Improvement in holders for screw-cutting dies



Y Patented 0ct,24,1871.

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UNITED STATES PATENT OFFICE.

BENJAMIN L. WALKER, OF SING SING, NEW YORK.

Specification forming part of Letters Patent No. 120,351, dated October24, 1871.

To all whom it may concern:

Be it known that I, BENJAMIN L. WALKER, of Sing Sing, in the county ofWestchester and State of New York, have invented a certain new anduseful Improvement in Holders for Screw- Cutting Dies while being tappedor cut; and I do hereby declare that the following is a full, clear, andexact description of the same, reference being had to the accompanyingdrawing forming part of this specification, and in which- Figure lrepresents a front viewoimyimproved holder with dies therein; Fig. 2, anend view of the same 5 and Fig. 3, a transverse section through the line.r a: in Fig. l.

Similar letters of reference indicate corresponding parts throughout theseveral figures.

My invention relates to a holder for tapping or cutting thescrew-threads in dies, or for recutting the latter by means ofa mastertap iirmly held by any suitable tool-holder7 and centered in relationwith the dies, as by a tool-holder adjustable in a straight course alongthe shears of a lathe, while the dies are rotated by a mandrel inconcentric position therewith; and the invention consists in a novelconstruction of the dieholder, whereby provision is made for setting oradjusting the dies so that they may be set and retained true in variousdirections for the passage ofthe master tap through them. Dies thus cutare truer and more perfect than when cut in the ordinary way.

Referring to the accompanying drawing, A represents the frame of thedie-holder provided with a central back socket or extension b forattachment ofthe holder to a revolving mandrelas, for insta-nce, alathe-chuck is carried and driven. Said frame is formed of a back,sides, and ends, the one c of which latter may be removably attached soas to open and close to fa cilitate the entry and release of the diesand their clamping-strips. A convenient provision for this purpose is tosecure the end piece c as by screws d d, and to make a slot, e, in theend piece c, so that by simply slackening the olie screw which fitsthrough said slot, the end piece c may be swung to one side from theother screw as a center of motion when it is desired to open the frame.B B are the dies and O O the clampingstrips, which latter are beveled ontheir inner sides to conform with the bevel of the dies, and are iittedso as to be capable of adjustment across or from side to side and withinthe holder. Both dies are secured at their sides and adjustablelaterally in common by these clamping strips which may extend the fulllength of the interior ofthe irame, but not so that they bind, and withprovision for their lateral adjust-nient at different points, as by adjListing and clamping-screws j' f. The dies B B are adjustable lengthwisewithin these strips, and clamped at their ends by means of end-screws gg. To set the dies inline on their faces a rocker, l), having an eye inits center, is caused to bear, as by projections h h, on both dies andmade adjustable from opposite ends by screws Ai z' iitted to enter thesides of the frame. By these combinations of devices the dies may be setand kept exactly truc and in perfect line every way as re quired.

What is here claimed, and desired to be secured by Letters Patent, is-

1. The combination of the frame A, with its end screws gg, theclamping-strips C O with their side-adjusting and clampingscrews ff, andthe rocker D adjustable as by screws i z', substantially as specified.

2. The frame A, constructed with a swinging opening end piece, c,slotted as at e, and secured by a bolt or bolts, in combination with theadj ustable clamping-strips O (l, essentially as herein set forth.

BENJ. L. WALKER. Witnesses:

G. B. HUBBELL,

EDGAR GREEN. (14.)

